US 7088289 B1 Abstract The invention is related to a communication terminal, including means for determining possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; means for selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible weight factor combinations; means for determining an optimum antenna weight factor by using the primary antenna weight factors; and means for signalling the optimum antenna weight factor to a network element.
Claims(26) 1. An antenna adaptation method in a communication system, the communication system comprising at least one network element and at least one communication terminal, the method comprising:
determining possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations;
determining an optimum antenna weight factor by using the primary antenna weight factors; and
signalling the optimum antenna weight factor to the network element.
2. The method of
3. The method of
4. The method of
5. The method of
6. A communication terminal, comprising:
means for determining possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
means for selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations;
means for determining an optimum antenna weight factor by using the primary antenna weight factors; and
means for signalling the optimum antenna weight factor to a network element.
7. A communication terminal, comprising:
means for storing possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
means for selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations;
means for determining an optimum antenna weight factor by using the primary antenna weight factors; and
means for signalling the optimum antenna weight factor to a network element.
8. A device, comprising:
means for determining possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
means for selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations;
means for determining an optimum antenna weight factor by using the primary antenna weight factors; and
means for signalling the optimum antenna weight factor to a network element.
9. A device, comprising:
means for storing possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
means for signalling the optimum antenna weight factor to a network element.
10. The device of
11. The device of
12. The device of
13. The device of
14. A computer program product encoding a computer program of instructions for executing a computer process for antenna adaptation, the process comprising:
determining possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations;
determining an optimum antenna weight factor by using the primary antenna weight factors; and
constructing a message for signalling the optimum antenna weight factor to a network element.
15. A computer program product encoding a computer program of instructions for executing a computer process for antenna adaptation, the process comprising:
storing possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations;
determining an optimum antenna weight factor by using the primary antenna weight factors; and
constructing a message for signalling the optimum antenna weight factor to a network element.
16. The computer program product of
17. The computer program product of
18. The computer program product of
19. A module, comprising:
means for determining possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
means for determining an optimum antenna weight factor by using the primary antenna weight factors.
20. A module, comprising:
means for storing possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
means for determining an optimum antenna weight factor by using the primary antenna weight factors.
21. A communication terminal, configured to:
first determine possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
select primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations;
second determine an optimum antenna weight factor by using the primary antenna weight factors; and
signal the optimum antenna weight factor to the network element.
22. A communication terminal, configured to:
store possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
select primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations;
determine an optimum antenna weight factor by using the primary antenna weight factors; and
signal the optimum antenna weight factor to the network element.
23. A device, configured to:
determine possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
select primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations;
determine an optimum antenna weight factor by using the primary antenna weight factors; and
signal the optimum antenna weight factor to the network element.
24. A device, configured to:
store possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
determine an optimum antenna weight factor by using the primary antenna weight factors; and
signal the optimum antenna weight factor to the network element.
25. A module, configured to:
determine possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
determine an optimum antenna weight factor by using the primary antenna weight factors.
26. A module, configured to:
store possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase;
determine an optimum antenna weight factor by using the primary antenna weight factors.
Description The invention relates to an antenna adaptation method in a communication system, the communication system comprising at least one network element and at least one communication terminal, a communication terminal, a device, a module and a computer program product. The use of systems including multiple antennas, such as an antenna array, in radio communication applications is of interest because of the increased performance achieved with these systems. In an antenna group or in an antenna array, individual antenna elements are typically located close to one another, or approximately half a wavelength apart from one another. When adaptive antenna arrays are used, the basic principle is that radiation beams are narrow and they are directed as directly as possible at a desired receiver. One known method of using adaptive antenna arrays is that the most suitable beam is selected from various alternative beams. In a digital system, the directing of antenna beams in the uplink is typically implemented by dividing a signal in base band parts into I and Q branches and by multiplying in a complex manner (phase and amplitude) the signal of each antenna element by appropriate weighting coefficients. In this case, an adaptive antenna array comprises not only antennas but also a signal processor, which automatically adapts antenna beams by using a control algorithm. In Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network, UTRAN, the user terminal estimates radio channels and computes a phase adjustment and/or an amplitude (power) adjustment for adapting antennas of the UTRAN access point to maximise the power the user terminal receives. The user terminal signals the information on the phase and/or power adjustment to the UTRAN access point (the network element). The problem is that in the closed loop mode According to an aspect of the invention, there is provided an antenna adaptation method in a communication system, the communication system comprising at least one network element and at least one communication terminal, the method comprising: determining possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; determining an optimum antenna weight factor by using the primary antenna weight factors; and signalling the optimum antenna weight factor to the network element. According to an aspect of the invention, there is provided a communication terminal, comprising: means for determining possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; means for selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; means for determining an optimum antenna weight factor by using the primary antenna weight factors; and means for signalling the optimum antenna weight factor to a network element. According to an aspect of the invention, there is provided a communication terminal, comprising: means for storing possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; means for selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; means for determining an optimum antenna weight factor by using the primary antenna weight factors; and means for signalling the optimum antenna weight factor to a network element. According to an aspect of the invention, there is provided a device, comprising: means for determining possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; means for selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; means for determining an optimum antenna weight factor by using the primary antenna weight factors; and means for signalling the optimum antenna weight factor to a network element. According to an aspect of the invention, there is provided a device, comprising: means for storing possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; means for selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; means for determining an optimum antenna weight factor by using the primary antenna weight factors; and means for signalling the optimum antenna weight factor to a network element. According to an aspect of the invention, there is provided a computer program product encoding a computer program of instructions for executing a computer process for antenna adaptation, the process comprising: determining possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; determining an optimum antenna weight factor by using the primary antenna weight factors; and constructing a message for signalling the optimum antenna weight factor to a network element. According to an aspect of the invention, there is provided a computer program product encoding a computer program of instructions for executing a computer process for antenna adaptation, the process comprising: storing possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; determining an optimum antenna weight factor by using the primary antenna weight factors; and constructing a message for signalling the optimum antenna weight factor to a network element. According to another aspect of the invention, there is provided a module, comprising: means for determining possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; means for selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; means for determining an optimum antenna weight factor by using the primary antenna weight factors. According to another aspect of the invention, there is provided a module, comprising: means for storing possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; means for selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; means for determining an optimum antenna weight factor by using the primary antenna weight factors. According to another aspect of the invention, there is provided a communication terminal, configured to: first determine possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; select primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; second determine an optimum antenna weight factor by using the primary antenna weight factors; and signal the optimum antenna weight factor to the network element. According to another aspect of the invention, there is provided a communication terminal, configured to: store possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; select primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; determine an optimum antenna weight factor by using the primary antenna weight factors; and signal the optimum antenna weight factor to the network element. According to another aspect of the invention, there is provided a device, configured to: determine possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; select primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; determine an optimum antenna weight factor by using the primary antenna weight factors; and signal the optimum antenna weight factor to the network element. According to another aspect of the invention, there is provided a device, configured to: store possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; select primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; determine an optimum antenna weight factor by using the primary antenna weight factors; and signal the optimum antenna weight factor to the network element. According to another aspect of the invention, there is provided a module, configured to: determine possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; select primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; determine an optimum antenna weight factor by using the primary antenna weight factors. According to another aspect of the invention, there is provided a module, configured to: store possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; select primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible antenna weight factor combinations; determine an optimum antenna weight factor by using the primary antenna weight factors. The invention provides several advantages. In an embodiment of the invention, the computation of the optimal phase and/or antenna adjustment is substantially simplified and thus quicker. In the following, the invention will be described in greater detail with reference to the embodiments and the accompanying drawings, in which With reference to It is clear to a person skilled in the art that the embodiments of the invention can be applied to systems utilizing different modulation methods or air interface standards. The cellular radio system can also communicate with other networks, such as a public switched telephone network or the Internet. The transmitter is coupled to an antenna array including two antennas In block Channel coding, interleaving and spreading/scrambling are carried out in a non-diversity mode. The spreading/scrambling is typically carried out by multiplying a signal with a selected pseudo-random code. The multiplying is depicted in A complex valued wide-band signal is fed to both transmission antenna branches (the first branch includes multiplier In the closed loop mode The user terminal uses the Common Pilot Channel (CPICH) to estimate the uplink radio channels. Once in every time slot, the user terminal computes a phase adjustment factor and/or an amplitude (power) adjustment factor to be applied at the UTRAN access point to maximise the power received by the user terminal. The user terminal transmits the information on the phase and/or power settings to the UTRAN access point. Feedback Signalling Message (FSM) bits are transmitted in the D-sub field of the FBI field. The D-sub field is dedicated to the signalling concerning the transmit diversity of the closed loop mode. The adjustments are carried out at the UTRAN Access Point at the beginning of the downlink DPCCH pilot field. In the closed loop mode The prior art amplitude and phase adjusting by using weight factors is explained in further detail in 3GPP TS 25.214 standard (3GPP=3rd Generation Partnership Project). Next, an embodiment of the antenna adaptation method is explained in further detail by means of In block In In block Instead of testing all possible FSM combinations as in prior art, only selected primary antenna weight factors are tested. The primary antenna weight factors are defined in this embodiment for phase, while power is kept constant for all antennas. Primary antenna weights are chosen to be perpendicular to decision boundaries that are bisectors of the angles between a minimum phase offset and a maximum phase offset depicted in In the following, the prior art calculation is explained in greater detail by means of In In Also in In Also in Also in Also in In In Recommendable primary antenna weight factors for phase adjustment for an antenna array comprising two antennas are listed in table 1. Notation x is used in table 1, when the FBI bit is allowed to be either 0 or 1.
Variables b In block For two antennas, the received power with different phase and/or power adjustment may be calculated as follows:
wherein f denotes a receiver finger index, N a denotes amplitude for transmit antenna ĥ w(p) denotes a primary antenna weight factor, ĥ Σ denotes a summation operation. The selection of the optimum antenna weight factor may be calculated as follows:
P Max denotes for the maximum. Next, an example of the lightened testing is explained in further detail by means of Bits, which may be either 1 or 0, are marked with x in the blocks illustrating FSM messages. In the example, instead of testing all potential FSM messages, only two combined phase and power adjustment coefficients, i.e. primary antenna weight factors, are tested. The primary antenna weight factors are chosen to be perpendicular to the decision boundaries that are bisectors of angles between the minimum and the maximum phase offset. In Recommendable primary antenna weight factors for phase adjustment for an antenna array comprising two antennas are listed in table 1. In In In Also in In In As can be seen by comparing In block The embodiment ends in block Underneath is presented a table illustrating the decrease in the computational complexity attained by the embodiment:
The embodiments may be realized in an electronic device, including a controller. The controller may be configured to perform at least some of the steps described in connection with the flowchart of The embodiments may be implemented as a computer program comprising instructions for executing a computer process for determining possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible weight factor combinations; and determining an optimum antenna weight factor by using the primary antenna weight factors. The terminal comprises an antenna The terminal further comprises a transmitter The user terminal also comprises a control block Furthermore, in spread-spectrum systems, such as wideband code division multiple access (WCDMA used in UMTS) systems, the spectrum of the signal is spread at the transmitter by means of a pseudo-random spreading code over a wide band and despread at the receiver, in an attempt to increase the channel capacity. The control block also comprises means for arranging the signal to be transmitted and the signalling information to conform to the air interface standard of the system used. In the embodiment, the control block comprises means for determining possible antenna weight factor combinations, selecting primary phase antenna weight factors, determining an optimum antenna weight factor and signalling the optimum antenna weight factor to the network element via the transmitter and the antenna. The user interface of the terminal comprises a loudspeaker or an earpiece The embodiments of the antenna adaptation method can mainly be implemented by software in the control block including, for instance, instructions for executing a computer process for antenna adaptation, the process comprising: storing possible antenna weight factor combinations, an antenna weight factor combination comprising an antenna weight factor for both power and phase; selecting primary antenna weight factors on the basis of bisectors of angles between a minimum phase offset and a maximum phase offset of the possible weight factor combinations; and determining an optimum antenna weight factor by using the primary antenna weight factors. Different hardware implementations are also feasible, e.g. a circuit built of separate logics components or one or more client-specific integrated circuits (Application-Specific Integrated Circuit, ASIC). A hybrid of software and hardware implementations is also feasible. The embodiments of the antenna adaptation method can also be implemented as a module that may be installed, for instance, to a communication terminal. Even though the invention has been described above with reference to an example according to the accompanying drawings, it is clear that the invention is not restricted thereto but it can be modified in several ways within the scope of the appended claims. Patent Citations
Non-Patent Citations
Referenced by
Classifications
Legal Events
Rotate |